2025/11/22 by Nashed, G. G. L.
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysics of Galaxies (astro-ph.GA) #Cosmology and Gravitation Theories #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #High Energy Physics - Theory (hep-th) #Pulsars and Gravitational Waves Research
paper · doi:10.48550/arxiv.2511.18017
openalex publication_date 2025/11/22 · openalex created_date 2025/11/27 · openalex updated_date 2026/07/28
In this work we examine the internal structure of compact stars within an extended gravitational framework described by the function f(R,G,T). Throughout this work, the quantity R refers to the curvature scalar formed from the Ricci tensor. The term G denotes the Gauss--Bonnet curvature invariant, while T corresponds to the trace obtained by contracting the matter energy-momentum tensor. Our analysis is directed toward massive radio pulsars with masses above 1.8 M\odot, which provide an exceptional testing ground for gravity under conditions inaccessible to laboratory experiments. Adopting the linear form f(R,G,T)=R+α G+β T where α and β are parameters of suitable dimensionality,\footnoteα has dimensions of [L2] and β carries units of [N-1]. we obtain an exact analytic solution for static anisotropic stellar matter in hydrostatic equilibrium. This solution allows all physical quantities to be expressed in terms of the dimensionless parameters α1=α/R2, β1=β/κ2 together with the compactness C=2GM/(Rc2). We constraint the two parameters α and β by matching the model with the mass and radius of pulsar U1724 requires restricting these parameters to α1=±0.023 and β1=±0.001, where κ2=8πG/c4 is the standard Einstein coupling. The resulting stellar configuration satisfies the causal bound on the radial sound speed, cs2